Radio/tape Cd Player problems of the 2014 Toyota 4Runner

This complaint relates to a defect in the Toyota entune premium audio system with navigation. Audio software version 0101a5. Unit is produced by panasonic. Model 57080. The system randomly and without warning "freezes" thereby preventing the driver from lowering or muting radio volume. The volume cannot be lowered or muted until the vehicle is stopped, and the ignition is turned off. The reverse safety camera will not activate when the head unit is in its "frozen" state. Toyota motor sales USA entune support department has been contacted about this issue, and I have a case number. They have not been able to provide any fix for the issue other than to contact dealer. Dealer states radio unit is defective, and I must pay out of my pocket to replace. A Toyota TSB exists to address this precise "freezing" issue, however, my particular unit will not accept the Toyota firmware update (software 0101b1) for reasons nobody has been able to determine. Toyota should replace the radio/head unit at their expense. I purchased the vehicle in March of 2017, it had 13,000 miles on it at time of purchase. Warranty expired shortly after I discovered this problem. In one incident, an emergency vehicle had its siren activated on the highway; I vaguely heard the siren, and attempted to lower the radio volume. The volume would not lower, and I became disoriented as to the location of the siren. It is dangerous that the radio control "freezes" while continuing to produce sound through the speakers, and the only way to turn it off is to shut off the vehicle.